Owens Corning Positioned for Growth

Owens Corning Positioned for Growth Q1 2015 This presentation shared at the following events: 3/17/15 Owens Corning Roadshow New York Thierry Denis, Vice President Investor Relations 3/12/15 OC Roadshow Hosted by Longbow Boston Brian Chambers, President Roofing & Asphalt Business 2/26/15 Barclay s Symposium New York Michael McMurray, Chief Financial Officer 2/24/15 OC Roadshow Hosted by SunTrust Dallas & Houston Michael McMurray, Chief Financial Officer 2/18/15 OC Roadshow Hosted by JP Morgan Paris, Frankfurt & Zurich Arnaud Genis, President Composites Business

Forward-Looking Statements and Non-GAAP Measures This presentation consists of this slide deck and the associated remarks and comments, all of which are integrally related and are intended to be presented and understood together. This presentation contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. These forward-looking statements can be identified by words such as anticipate, appear, assume, believe, estimate, expect, forecast, intend, may, plan, should, seek, will, and other terms of similar meaning or import in connection with any discussion of future operating, financial or other performance that reference future periods. We caution you against relying on these statements as they involve risks and uncertainties that are difficult to predict and the Company s actual results may differ materially from those projected in these statements. Our future performance may be affected by risks and uncertainties including, without limitation, levels of residential and commercial construction activity; competitive and pricing factors; levels of global industrial production; demand for our products; relationships with key customers; industry and economic conditions that affect the market and operating conditions of our customers, suppliers or lenders; our level of indebtedness; weather conditions; availability and cost of credit; availability and cost of energy and raw materials; issues involving implementation and protection of information technology systems; international economic and political conditions, including new legislation or other governmental actions; our ability to utilize our net operating loss carry-forwards; research and development activities and intellectual property protection; foreign exchange and commodity price fluctuations; interest rate movements; labor disputes and litigation; uninsured losses; issues related to acquisitions, divestitures and joint ventures; achievement of expected synergies, cost reductions and/or productivity improvements; defined benefit plan funding obligations; and, factors detailed from time to time in the Company s U.S. Securities and Exchange Commission ( SEC ) filings. For purposes of this presentation, any discussion referring to year to date or last twelve months ( LTM ) refers to the period ended on the last calendar day of the quarter preceding the date of the investor event referred to on the first page of this document. Otherwise the information in this presentation speaks as of the date of the investor event, and is subject to change. The Company does not undertake any obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise except as required by federal securities laws. Any distribution of this presentation after the date of the investor event is not intended and should not be construed as updating or confirming such information. This presentation contains references to certain "non-gaap financial measures" as defined by the SEC. Management uses non-gaap measures for various purposes, including reporting results of operations to the Board of Directors, analysis of performance and related employee compensation measures. Although management believes these measures, and exclusions from GAAP therein, provide a useful representation of performance, non-gaap measures should not be considered in isolation or as a substitute for GAAP measures. A reconciliation of these non-gaap financial measures to their most directly comparable financial measures calculated and presented in accordance with generally accepted accounting principles can be found in Appendix A. Adjusted EBIT is earnings before interest, taxes and other items that management does not allocate to our segment results because it believes they are not a result of the Company s current operations. 2

Owens Corning at a Glance Founded in 1938, an industry leader in glass fiber insulation, roofing and glass fiber reinforcements 2014 net sales: $5.3 billion 14,000 employees in 25 countries Fortune 500 company for 60 consecutive years Component of Dow Jones Sustainability World Index for five consecutive years 3

Investment Highlights Composites Roofing Market-leading business with improving economic conditions and higher utilization rates Strong market position in consolidated industry Insulation Progress supports confidence in return to historical profitability Three Market-Leading Businesses 4

Full-Year 2014 Highlights and Outlook Maintained a very high level of safety performance in 2014 Board declared 6% dividend increase Delivered adjusted EBIT of $412 million Insulation delivered 14 th consecutive quarter of EBIT growth; increased full-year EBIT by $68 million Composites delivered 6 th consecutive quarter of EBIT improvement; grew 2014 earnings by 50% Roofing achieved commercial objectives for the second half Anticipate continued growth in U.S. housing starts and global industrial production in 2015 5

Strong Portfolio Positioned for Growth 94 95 96 97 98 99 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 Insulation Roofing Composites Margin >= 10% 0%<= Margin < 10% Margin < 0% Sources: Owens Corning s SEC filings since 2006. For comparability purposes, prior years have been provided based on Owens Corning s SEC filings, internal management reports, and management estimates. 6

Insulation Business Q4 & Full-Year 2014 Highlights Delivered full-year EBIT of $108 million, a $68 million increase versus last year Achieved operating leverage of over 50% in 2014 Expect 2015 results to benefit from growth in U.S. new construction, pricing, and operating leverage $ (in millions) Q4 2014 Q4 2013 2014 2013 Net sales* $490 $466 $1,746 $1,642 EBIT $46 $39 $108 $40 EBIT as % of sales 9% 8% 6% 2% D&A $25 $25 $101 $104 * before inter-segment eliminations 2014 Revenue by End Market* U.S. & Canada Commercial & Industrial 24% $2,000 $1,500 Five-Year Financial Performance 10% 5% U.S.& Canada Residential Repair & Remodeling 20% U.S. & Canada New Residential Construction 40% $1,000 $500 0% -5% International 16% *Owens Corning management estimates; estimated error margin below 5% $0 2010 2011 2012 2013 2014 Sales* EBIT as % of sales *In millions -10% Source: Owens Corning management estimates and Owens Corning SEC filings; comparability may differ over time 7

Owens Corning Insulation EBIT Progress $40 Q1 Q2 Q3 Q4 43 39 47 of Dollars $20 $0 1 4 18 3 18 0 9 EBIT in Millions -$20 -$40 -$60-47 -34-21 -38-16 -12 -$80 2011 Actual 2012 Actual 2013 Actual 2014 Actual Consistent Quarterly EBIT Progression Since 2011 Source: Owens Corning quarterly and annual SEC filings 8

Owens Corning Insulation Well Positioned to Return to Historical Margins 30% EBIT Margin Avg EBIT Margin '85-'08 (15%) 20% 10% 0% -10% '84 '86 '88 '90 '92 '94 '96 '98 '00 '02 '04 '06 '08 '10 '12 '14 Historically Delivered 15% EBIT Margins at 1.5 Million Housing Starts Source: Owens Corning management estimates and Owens Corning SEC filings, comparability may differ over time; 9

Insulation Industry North American Fiberglass 100% 80% 2015 Industry Capacity Utilization 90% 80% 70% 60% 40% 20% 0% Total Capacity Operating Plants Operating Lines Capacity Utilization Tightening as U.S. Housing Recovers Source: Owens Corning management estimates as of February 2015 rounded to nearest 5%. Products sold primarily to North American residential market. Excludes heavy density and loosefill products. Based on 2015 estimate of 1.1MM unlagged U.S. housing starts and other macro assumptions. 10

Owens Corning Insulation North American Fiberglass Network Edmonton Candiac Toronto Delmar Santa Clara Nephi Kansas City Mt. Vernon Newark Eloy 2015 Estimated Average Utilization: Near full capacity Below full capacity Not in operation Waxahachie Fairburn Lakeland Continued Discipline in OC Capacity Management Capacity utilization based as on estimated average 2015 total insulation production using melter capacity Source: Owens Corning management estimates 11

Positioned to Grow with Our Markets Insulation End-Use Markets % of Full-Year 2014 Revenue U.S. and Canada Residential New Construction 40% Expected Market Growth Drivers Housing starts Building energy code adoption Household formation Mid-Term Growth U.S. and Canada Repair and Remodel 20% U.S. and Canada Commercial and Industrial 24% Aging housing stock Energy efficiency policies Code and green specification driven Owner/operator focus Latin America and Asia Pacific 16% Growing middle class Infrastructure improvements Urbanization of China Targeting Double-Digit Revenue Growth as Market Recovers Source: Owens Corning management estimates. 12

Roofing Business Q4 & Full-Year 2014 Highlights Full-year margins declined 7% on lower volumes and prices Achieved commercial objectives for the second half Market dynamics in the first half of 2015 will largely determine how the Roofing business performs versus last year $ (in millions) Q4 2014 Q4 2013 2014 2013 Net sales* $340 $381 $1,748 $1,967 EBIT $32 $55 $232 $386 EBIT as % of sales 9% 14% 13% 20% D&A $9 $10 $39 $38 * before inter-segment eliminations 2014 Revenue by End Market* $2,400 Five-Year Financial Performance 30% U.S. & Canada Residential Repair & Remodeling 73% U.S. & Canada Commercial & Industrial 16% U.S. & Canada New Residential Construction 10% International 1% *Owens Corning management estimates; estimated error margin below 5% $2,000 $1,600 $1,200 $800 $400 $0 2010 2011 2012 2013 2014 Sales* EBIT as % of sales *In millions 25% 20% 15% 10% 5% 0% Source: Owens Corning management estimates and Owens Corning SEC filings; comparability may differ over time 13

U.S. Asphalt Shingle Industry Consolidation 70s 80s 90s Current OC FRY GAF ELK CERTAINTEED TAMKO CELOTEX MANVILLE IKO BIRD ATLAS GEORGIA PACIFIC FLINTKOTE GLOBE PABCO MALARKEY LUNDAY THAGARD CUSTOM ROOFING BIG CHIEF BEAR PHILIP CAREY OC GAF ELK CERTAINTEED TAMKO CELOTEX MANVILLE IKO BIRD ATLAS GEORGIA PACIFIC GENSTAR GLOBE PABCO MALARKEY LUNDAY THAGARD CUSTOM ROOFING OC GAF ELK CERTAINTEED TAMKO CELOTEX IKO ATLAS GEORGIA PACIFIC GS ROOFING GLOBE PABCO MALARKEY OC GAF/ELK CERTAINTEED TAMKO IKO ATLAS PABCO MALARKEY Top 90% 16 13 10 4 Total 21 17 13 8 Favorable Industry Structure for the Future Source: Owens Corning management estimates and various industry sources and publications 14

U.S. Asphalt Shingle Market MM Sq. Major Storms MM 180 3 Re-roof Demand New construction 3 2 3 7 8 18 8 3 22 17 Total Existing Home Sales 19 11 7.5 6 6 6 107 103 109 110 113 116 116 112 100 96 93 91 93 94 88 83 0 33 30 31 32 34 37 39 35 26 17 11 11 11 14 17 18 '99 '00 '01 '02 '03 '04 '05 '06 '07 '08 '09 '10 '11 '12 '13 '14 0.0 Total 143 136 143 144 154 161 173 155 129 135 120 108 122 118 111 107 Source: Asphalt Roofing Manufacturers Association, Summary of Asphalt Roofing Industry Shipments. National Association of Realtors existing home sales and Owens Corning management estimates 15

Strong Market Position in Consolidated Industry Track record of strong financial performance Delivered average operating margins in excess of 20% during 2009-2013 period Re-roof demand over the last few years has been sluggish Housing activity forecasts support some demand growth Glass fiber mat and laminate advancements in the 1980s and 1990s could be extending replacement cycle Soft demand and competitive activity put pressure on margins in 2014 Strong market position; outlook for 2015 largely determined by competitive pricing dynamics, asphalt cost deflation, and market demand 16

Composites Business Q4 & Full-Year 2014 Highlights Achieved $149 million of EBIT in 2014; grew earnings by 50% versus last year Delivered $32 million of price benefit in 2014, with six consecutive quarters of improvement In 2015, expect price to drive majority of EBIT improvement $ (in millions) Q4 2014 Q4 2013 2014 2013 Net sales* $464 $461 $1,935 $1,845 EBIT $53 $36 $149 $98 EBIT as % of sales 11% 8% 8% 5% D&A $30 $31 $129 $130 * before inter-segment eliminations U.S. & Canada Commercial & Industrial 28% 2014 Revenue by End Market* U.S. & Canada New Residential Construction 3% $2,400 $1,800 Five-Year Financial Performance 15% 10% U.S. & Canada Residential Repair & Remodeling 8% International 61% *Owens Corning management estimates; estimated error margin below 5% $1,200 $600 $0 2010 2011 2012 2013 2014 Sales* EBIT as % of sales *In millions 5% 0% -5% Source: Owens Corning management estimates and Owens Corning SEC filings; comparability may differ over time 17

Glass Fiber A $7.5 Billion Global Market Appliances Electronics Recreation Wind 9% Residential Commercial Water transportation & storage Consumer 16% Construction 34% Factories Mining Offshore platforms Industrial 13% Transportation 28% Cars Trucks, buses, trains Marine A Key Material Enabling Solutions Essential to Everyday Life Glass reinforcements market defined as glass fiber reinforcements and direct conversion products as consumed, excluding yarns Source: Owens Corning management estimates as of Feb 2015 18

Owens Corning Composites Global megatrends, continued growth in industrial production, and material substitution support glass fiber market growth at a 5-7% CAGR Strategic focus on core building material markets with sustainable solutions Cost Leadership Price Realization Product Leadership Capital Efficiency Clear agenda to deliver improved returns Leader in an Industry Entering a Phase of Supply Tension Source: Owens Corning management estimates as of February 2015 19

Owens Corning Composites Positioned to Win #1 Position Emerging Position 25% Europe 30% 26% China 10% % Market Revenue % OC Revenue % Market Revenue % OC Revenue #1 Position Americas 34% 46% OC glass fiber manufacturing site OC downstream fabrication site #1 Position Rest of World 15% 14% % Market Revenue % OC Revenue % Market Revenue % OC Revenue Leading Market Positions and an Unrivaled Supply Network Sources: Owens Corning management estimates % Market Revenue = market revenue in region as % of 2014 global market size % OC Revenue = OC revenue in region as % of OC Composites global 2014 sales Glass reinforcements market defined as glass fiber reinforcements and direct conversion products as consumed, excluding yarns 20

Glass Fiber Market Demand 5,000 4,000 Glass Fiber Demand Has Grown at 1.6 Multiple of Industrial Production Growth Glass Fibe er K Tons 3,000 2,000 1,000-1981 1992 2003 2014 Historical Glass Fiber Market Growth Averaging 5% Glass fiber market demand excludes E-glass yarns Sources: Fiber Economics Bureau, Glass Fiber Europe, Global Trade Information Services, Inc. and Owens Corning management estimates 21

Glass Fiber Industry Estimated Capacity China Emergence Capacity Overbuild Macro Adjustment Excess Inventory Supply Tension Improved Returns 100% 2004 2006 2008 2010 2012 2014 2016 1.7 Estimated Capacity Utilization 90% 80% 70% 60% 0.5 1.1 0.4 0.8 0.5 90% Threshold (high probability additions) Change in global demand (MM T) Change in global capacity (MM T) 50% 0.1/ yr 0.3/ yr 0.4/ yr 0.1/ yr 0.2/ yr 0.1/ yr 2005-09 2010-12 2013-16 Tighter Capacity Environment Expected in the Near Term Glass fiber market demand excludes E-glass yarns Sources: Fiber Economics Bureau, Glass Fiber Europe, Global Trade Information Services, Inc. and Owens Corning management estimates as of February 2015 22

Owens Corning Composites Focused on Creating Shareholder Value Significant actions, including capital and cash restructuring, to achieve goal of 75% low-delivered cost Extensive restructuring of high-cost assets in Europe, Japan and Canada Successful sale and closure of a high-cost facility in China Constructed several new low-cost production lines, while essentially maintaining flat overall capacity Entered into creative alliances with China-based manufacturers Suspended melting capacity investments since 2012 Delivered six consecutive quarters of price improvement Business Actions Have Contributed to ROC Improvement 23

Sustaining a Strong Balance Sheet Maintaining investment-grade financial strength is a pillar of Owens Corning s strategy Maintained investment-grade credit ratings from Standard & Poor's and Fitch $800 million revolving credit facility maturing in 2018 $250 million accounts receivable securitization facility maturing in 2018 $1.8 billion senior notes outstanding with 2016, 2019, 2022, 2024 and 2036 maturities Ample liquidity to support growth Capital markets remain open to Owens Corning 24

Tax Position is a Significant Asset Benefit from $2.2 billion NOL with estimated present value of approximately $5 per share Delivering cash tax savings of about $60 million per year Expect long-term book tax rate of 30% to 32% based on geographic mix of earnings and tax planning Cash tax rate of 10% to 12% over the next few years Source: Owens Corning management estimates 25

Disciplined Capital Allocation Strategy Drive shareholder returns by enabling organic and inorganic growth and supporting the balance sheet Maintain investment grade Capital allocation strategy Investing in attractive organic growth Returning excess cash to shareholders Pursuing value-creating acquisitions Quarterly dividend initiated in 2014 conveys confidence in long-term financial outlook and cash flow generation; 6% dividend increase announced in 2015 As of December 31, 2014, 7.7 million shares remain available for repurchase under existing authorization 26

Key Financial Data ($ in millions, except per share data) 2014 2013 Q4 2014 Q4 2013 Net sales $5,276 $5,295 $1,261 $1,278 Net earnings attributable to Owens Corning $226 $204 $33 $82 Diluted earnings per share attributable to Owens Corning common stockholders $1.91 $1.71 $0.28 $0.69 Earnings before interest and taxes (EBIT) $392 $385 $104 $104 Adjusted EBIT $412 $416 $107 $96 Adjusted Earnings $208 $221 $55 $52 Adjusted EPS (diluted) $1.76 $1.86 $0.47 $0.44 Adjusted EBIT as a % of sales 8% 8% 8% 8% Marketing and administrative expenses $487 $530 $115 $135 Depreciation and amortization $304 $332 $75 $97 Cash flow from operating activities $441 $407 $379 $249 Total debt (excluding rate swap), net of cash $1,950 $1,955 $1,950 $1,955 27

2015 Corporate Environment & Guidance Macro Environment Continued growth in U.S. housing starts; generally forecasted in 1,100,000-1,200,000 range Moderate global industrial production growth Primary Guidance Insulation: should continue to benefit from growth in U.S. residential new construction, improved pricing and operating leverage Composites: expect majority of EBIT improvement to come from price Roofing: market dynamics in the first half of the year will largely determine how the business performs relative to 2014 Other Guidance Items Corporate expenses of $120-$130MM Interest expenses about $110MM Capital expenditures about $355MM, including about $55 million for the completion of construction of a non-woven facility Depreciation & amortization about $310MM Cash tax rate of 10-12% and book tax rate of 30-32%* on adjusted pre-tax earnings * Excluding significant tax reserve reversals Source: Owens Corning management estimates as of February 2015 28

Appendix A Non-GAAP Reconciliations 29

Appendix A Non-GAAP Reconciliations 30